Electronic devices, such as mobile phones, having touch sensors for detecting contact by users have been on the increase in recent years. Various contact detection methods such as resistive method and capacitive method are known, each of which detects the contact of a contact object such as a user's finger or a stylus.
Electronic devices having touch sensors not only on the front surface but also on the back surface are known, too. For example, Patent Literature (PTL) 1 describes a mobile terminal that includes two touch sensors on each of the front surface and the back surface, and provides improved convenience by receiving, based on a predetermined correspondence relationship associated with a use state, an input to a first back surface or a second back surface as an input to a first front surface or a second front surface.